To a certain extent, the authors are clearly right that many statutes play as crucial a role in the operation of government as the Constitution. The difficulty, though, is in determining which “superstatutes” constitute our “small-c constitution” and how these statutes became super.
Eskridge and Ferejohn’s list of superstatutes is fairly expansive. It includes, among others, the “constitution of equality,” exemplified by the Civil Rights Act; the “constitution of democracy,” exemplified by the Voting Rights Act; the “constitution of the market,” exemplified by antitrust law and financial regulations; the “monetary constitution,” exemplified by the Federal Reserve Act.

How do these statutory schemes become super?

Eskridge and Ferejohn posit a causal sequence. A political entrepreneur puts a problem on the public agenda . . . . Opponents predict disastrous consequences or condemn the proposal as inconsistent with “core national commitments.” A process of political argument unfolds, eventually producing a statute whose supporters are temporarily riding high in the saddle. But the statute becomes super only over the course of subsequent years, if confirmed and expanded by further rounds of political action. New legislation that reaffirms the statute’s central principles, or (even more likely) administrative interpretation monitored by judges and congressional committees, may effectively cement the statute in the working constitution.

Constitutional scholar Charles Beard defined constitutional law as “that body of law relative to the fundamental organization of the three branches of the federal government.” Similarly, English legal theorist Albert Venn Dicey defined it as “all rules which directly or indirectly affect the distribution or the exercise of the sovereign power in the state.” At first glance, and as the reviewer argues, Eskridge and Ferejohn seem to reject what these, what we may call, procedural-structural definitions. The reviewer concludes that they ultimately fail to articulate a systematic approach.

Eskridge’s and Ferejohn’s treatment of the statutory constitution is so capacious, the boundaries of their enterprise so ill-defined, that it threatens to swallow up all of ordinary politics. . . . [I]f everything is constitutional, nothing is.

I can’t evaluate the reviewer’s claim about Eskridge and Ferejohn as I didn’t read the book. But based on the reviewer’s description, I think one may reasonably read Beard’s and Dicey’s procedural-structural definitions of constitutional law broadly enough to include Eskridge and Ferejohn’s policy-oriented examples.

In many ways, the “fundamental organization” of our government and the “distribution . . . of the sovereign power” is influenced by certain core values that permeate the legal system. More specifically, our written, big-C Constitution is often construed in light of those values.

For example, the Equal Protection Clause of the 14th Amendment is read in light of modern notions of prejudice and racism, as embodied in Civil Rights Era legislation. Similarly, the Commerce Clause is read in light of modern notions capitalism, as embodied in our various regulatory statutes. These values, which are essentially policies preferences developed over many years and ultimately codified in statutes, influence the application of core aspects of the Constitution. Those statutes, in turn, become as much a part of constitutional law as the explicit constitutional text itself.